Solid-state imaging apparatus, imaging system, and distance measurement method

ABSTRACT

To improve accuracy of distance measurement using a Z pixel having the same size as size of a visible light pixel. In a solid-state imaging apparatus, a visible light converting block includes a plurality of visible light converting units in which light receiving faces for receiving visible light are disposed and configured to generate electric charges in accordance with a light receiving amount of the received visible light, and a visible light electric charge holding unit configured to exclusively hold the electric charges respectively generated by the plurality of visible light converting units in periods different from each other. An infrared light converting block includes a plurality of infrared light converting units in which light receiving faces which have substantially the same size as size of the light receiving faces of the visible light converting units and which receive infrared light are disposed and configured to generate electric charges in accordance with a light receiving amount of the received infrared light, and an infrared light electric charge holding unit configured to collectively and simultaneously hold the electric charges respectively generated by the plurality of infrared light converting units.

TECHNICAL FIELD

The present technology relates to a solid-state imaging apparatus, animaging system and a distance measurement method. More particularly, thepresent technology relates to a solid-state imaging apparatus having adistance measurement pixel for measuring a distance to a subject, animaging system and a distance measurement method for these.

BACKGROUND ART

In related art, an imaging system which measures a distance to a subjectby irradiating the subject with infrared light, receiving reflectedinfrared light and measuring a time period from irradiation to lightreception is used. Such a scheme which is referred to as a time offlight (TOF) scheme, is a scheme widely used to detect motion of thesubject or measure a three-dimensional shape. An imaging element used inthis imaging system is configured with a visible light pixel having aphotoelectric conversion element which converts visible light into anelectrical signal, and an infrared light pixel having a photoelectricconversion element which converts reflected infrared light into anelectrical signal. A distance is measured by this infrared light pixel.Here, such an infrared light pixel is referred to as a distancemeasurement pixel. Because, normally, infrared light attenuates in theprocess of propagation, in the case where an infrared light pixel havingthe same size as size of a visible light pixel is used as a distancemeasurement pixel, sensitivity of photoelectric conversion becomesinsufficient, and accuracy of distance measurement degrades. To preventthis, it is desirable to use a distance measurement pixel with highsensitivity. Therefore, a system is proposed which uses a distancemeasurement pixel having a photoelectric conversion element whoselight-receiving area is four times as large as a light-receiving area ofa photoelectric conversion element of a visible light pixel (see, forexample, Patent Literature 1).

CITATION LIST Patent Literature

Patent Literature 1: US Unexamined Patent Application Publication No.2006/0192086

DISCLOSURE OF INVENTION Technical Problem

In the above-described related art, a single photon avalanche diode(SPAD) is used as a photoelectric conversion element, and this SPADelement is configured to have a light receiving area four times as largeas that of a photoelectric conversion element of a visible light pixel.By this means, it is possible to measure a distance with weak reflectedlight by improving sensitivity of photoelectric conversion. However,because a distance measurement pixel having a larger area than that of avisible light pixel is required, it is necessary to manufacture animaging element in accordance with a design rule different from that fora normal imaging element. Therefore, there is a problem that it requireshigh cost.

The present technology has been created in view of such circumstancesand it is desirable to improve accuracy of distance measurement using adistance measurement pixel configured to have the same size as that of avisible light pixel.

Solution to Problem

The present technology has been made to solve the above problem.According to a first aspect of the present technology, a solid-stateimaging apparatus includes: a visible light converting block thatincludes a plurality of visible light converting units in which lightreceiving faces for receiving visible light are disposed and configuredto generate electric charges in accordance with a light receiving amountof the received visible light, and a visible light electric chargeholding unit configured to exclusively hold the electric chargesrespectively generated by the plurality of visible light convertingunits in periods different from each other; and an infrared lightconverting block that includes a plurality of infrared light convertingunits in which light receiving faces which have substantially the samesize as size of the light receiving faces of the visible lightconverting units and which receive infrared light are disposed andconfigured to generate electric charges in accordance with a lightreceiving amount of the received infrared light, and an infrared lightelectric charge holding unit configured to collectively andsimultaneously hold the electric charges respectively generated by theplurality of infrared light converting units. By this means, an effectthat electric charges respectively generated by the above-describedplurality of infrared light converting units are collectively held atthe same time is provided.

In addition, according to the first aspect, the visible light convertingblock may include the four visible light converting units and thevisible light electric charge holding unit. By this means, an effectthat the above-described visible light converting block has four visiblelight converting units is provided.

In addition, according to the first aspect, the infrared lightconverting block may include the four infrared light converting unitsand the infrared light electric charge holding unit. By this means, aneffect that the above-described infrared light converting block has fourinfrared light converting units is provided.

In addition, according to the first aspect, the infrared lightconverting block may include: the two infrared light converting units;the two visible light converting units; and the infrared light electriccharge holding unit configured to collectively and simultaneously holdthe electric charges respectively generated by the two infrared lightconverting units in the case of holding the electric charges generatedby the two infrared light converting units, and exclusively hold theelectric charges respectively generated by the two visible lightconverting units in periods different from each other in the case ofholding the electric charges generated by the two visible lightconverting units. By this means, an effect that the above-describedinfrared light converting block has two infrared light converting unitsand two visible light converting units is provided.

In addition, according to the first aspect, the visible light convertingblock may include the visible light electric charge holding unit and thefour visible light converting units in which a red light converting unitwhich is the visible light converting unit configured to generate theelectric charge in accordance with red light, a green light convertingunit which is the visible light converting unit configured to generatethe electric charge in accordance with green light, and a blue lightconverting unit which is the visible light converting unit configured togenerate the electric charge in accordance with blue light are arrangedin a Bayer array. By this means, an effect that the above-describedvisible light converting block has four visible light converting unitsdisposed in a Bayer array is provided.

In addition, according to the first aspect, the visible light convertingblock may include a red light converting unit which is the visible lightconverting unit configured to generate the electric charge in accordancewith red light, a green light converting unit which is the visible lightconverting unit configured to generate the electric charge in accordancewith green light, a blue light converting unit which is the visiblelight converting unit configured to generate the electric charge inaccordance with blue light, a white light converting unit which is thevisible light converting unit configured to generate the electric chargein accordance with white light, and the visible light electric chargeholding unit. By this means, an effect that the above-described visiblelight converting block has four visible light converting units of theabove-described red light converting unit, the above-described greenlight converting unit, the above-described blue light converting unitand the above-described white light converting unit is provided.

In addition, according to the first aspect, the infrared lightconverting block may further include an infrared light electric chargetransferring unit configured to transfer the electric chargesrespectively generated by the plurality of infrared light convertingunits to the infrared light electric charge holding unit by conductingelectricity between the plurality of infrared light converting units andthe infrared light electric charge holding unit at a same time. By thismeans, an effect that the above-described electric charges generated bythe above-described plurality of infrared light converting units aretransferred to the above-described infrared light holding unit at thesame time is provided.

In addition, according to the first aspect, the solid-state imagingapparatus may further include an infrared light signal generating unitconfigured to generate a signal in accordance with the electric chargeheld in the infrared light electric charge holding unit. By this means,an effect that a signal in accordance with the above-described electriccharges held in the above-described infrared light electric chargeholding unit is generated is provided.

In addition, according to a second aspect of the present technology, animaging system includes: an infrared light emitting unit configured toemit infrared light to a subject; a visible light converting block thatincludes a plurality of visible light converting units in which lightreceiving faces for receiving visible light are disposed and configuredto generate electric charges in accordance with a light receiving amountof the received visible light, and a visible light electric chargeholding unit configured to exclusively hold the electric chargesrespectively generated by the plurality of visible light convertingunits in periods different from each other; an infrared light convertingblock that includes a plurality of infrared light converting units inwhich light receiving faces which have substantially the same size assize of the light receiving faces of the visible light converting unitsand which receive infrared light emitted and reflected by the subjectare disposed and configured to generate electric charges in accordancewith a light receiving amount of the received infrared light, and aninfrared light electric charge holding unit configured to collectivelyand simultaneously hold the electric charges respectively generated bythe plurality of infrared light converting units; an infrared lightsignal generating unit configured to generate a signal in accordancewith the electric charge held in the infrared light electric chargeholding unit; and a distance measurement unit configured to measure adistance to the subject by measuring a time period from the emission atthe infrared light emitting unit to the light reception at the infraredlight converting unit of the infrared light converting block on thebasis of the generated signal. By this means, an effect that theelectric charges respectively generated by the above-described pluralityof infrared light converting units are collectively held at the sametime is provided.

In addition, according to a third aspect of the present technology, adistance measurement method includes: an infrared light emitting step ofemitting infrared light to a subject; an infrared light signalgenerating step of generating a signal in accordance with electriccharges held in an infrared light electric charge holding unit in aninfrared light converting block including a plurality of infrared lightconverting units in which light receiving faces which have substantiallythe same size as size of light receiving faces of visible lightconverting units in a visible light converting block and which receiveinfrared light emitted and reflected by the subject are disposed andconfigured to generate electric charges in accordance with a lightreceiving amount of the received infrared light and the infrared lightelectric charge holding unit configured to collectively andsimultaneously hold the electric charges respectively generated by theplurality of infrared light converting units, the visible lightconverting block including a plurality of visible light converting unitsin which the light receiving faces for receiving visible light aredisposed and configured to generate electric charges in accordance witha light receiving amount of the received visible light and a visiblelight electric charge holding unit configured to exclusively hold theelectric charges respectively generated by the plurality of visiblelight converting units in periods different from each other; and adistance measurement step of measuring a distance to the subject bymeasuring a time period from emission of the infrared light to the lightreception at the infrared light converting unit of the infrared lightblock on the basis of the generated signal. By this means, an effectthat the electric charges respectively generated by the above-describedplurality of infrared light converting units are collectively held atthe same time is provided.

Advantageous Effects of Invention

According to the present technology, it is possible to provide apreferred advantageous effect of improving accuracy of distancemeasurement using a distance measurement pixel having the same size asthat of a visible light pixel. Meanwhile, the effects described hereinare not necessarily limited and may be effects described in the presentdisclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of an imagingsystem 1 in an embodiment of the present technology.

FIG. 2 is a diagram illustrating a configuration example of asolid-state imaging apparatus 20 in the embodiment of the presenttechnology.

FIG. 3 is a diagram illustrating a configuration example of a pixel in afirst embodiment of the present technology.

FIG. 4 is a diagram illustrating an arrangement example of pixels in thefirst embodiment of the present technology.

FIG. 5 is a schematic diagram illustrating a configuration example of apixel in the first embodiment of the present technology.

FIG. 6 is a diagram illustrating a distance measurement method in thefirst embodiment of the present technology.

FIG. 7 is a diagram illustrating an infrared light converting block inthe first embodiment of the present technology.

FIG. 8 is a diagram illustrating relationship between an imaging periodand a distance measurement period in the first embodiment of the presenttechnology.

FIG. 9 is a diagram illustrating an imaging method in the firstembodiment of the present technology.

FIG. 10 is a diagram illustrating a distance measurement method in thefirst embodiment of the present technology.

FIG. 11 is a diagram illustrating an example of processing procedure ofdistance measurement in the first embodiment of the present technology.

FIG. 12 is a diagram illustrating a visible light converting block in amodified example of the first embodiment of the present technology.

FIG. 13 is a diagram illustrating an infrared light converting block ina second embodiment of the present technology.

FIG. 14 is a diagram illustrating relationship between an imaging periodand a distance measurement period in the second embodiment of thepresent technology.

FIG. 15 is a diagram illustrating an imaging method in the secondembodiment of the present technology.

FIG. 16 is a diagram illustrating an infrared light converting block ina third embodiment of the present technology.

FIG. 17 is a diagram illustrating a distance measurement method in thethird embodiment of the present technology.

FIG. 18 is a diagram illustrating an imaging method in the thirdembodiment of the present technology.

FIG. 19 is a diagram illustrating an infrared light converting block ina fourth embodiment of the present technology.

FIG. 20 is a diagram illustrating an arrangement example of pixels in afifth embodiment of the present technology.

FIG. 21 is a diagram illustrating a configuration example of a pixel inthe fifth embodiment of the present technology.

FIG. 22 is a diagram illustrating an imaging method in the fifthembodiment of the present technology.

MODES FOR CARRYING OUT THE INVENTION

Embodiments for implementing the present technology (hereinafter,referred to as embodiments) will be described below. Description will beprovided in the following order.

1. First embodiment (example in the case where infrared light convertingblock is configured with two infrared light converting pixels and twovisible light converting pixels)2. Second embodiment (example in the case where infrared light block isconfigured with four infrared light converting pixels)3. Third embodiment (example in the case where infrared light convertingblock is configured with one infrared light converting pixel and threevisible light converting pixels)4. Fourth embodiment (example in the case where infrared lightconverting pixels are disposed at positions of G pixels in Bayer array)5. Fifth embodiment (example in the case where two electric chargeholding units are connected to photoelectric converting unit)

1.First Embodiment Configuration of Imaging System

FIG. 1 is a diagram illustrating a configuration example of an imagingsystem 1 in an embodiment of the present technology. The imaging system1 includes a lens 10, a solid-state imaging apparatus 20, a signalprocessing unit 30, an image processing unit 40, a distance measurementunit 50 and an infrared light emitting unit 60.

The lens 10 optically forms an image of a subject to the solid-stateimaging apparatus 20. The solid-state imaging apparatus 20 converts theoptical image formed by the lens 10 into an image signal and outputs theimage signal. In the solid-state imaging apparatus 20, pixels forgenerating an image signal are disposed in two dimensions on a planewhere the optical image is formed. The pixels include a visible lightpixel for visible light and an infrared light pixel for infrared lightin the optical image.

The visible light pixel is a pixel for generating a signal in accordancewith received visible light, and examples of the visible light pixel caninclude three types of pixels of a pixel for generating a signal inaccordance with red light (R pixel), a pixel for generating a signal inaccordance with green light (G pixel) and a pixel for generating asignal in accordance with blue light (B pixel). An image signal of asubject is formed with a visible light signal which is a signalgenerated by these pixels.

Meanwhile, the infrared light pixel is a pixel for generating aninfrared signal which is a signal in accordance with received infraredlight. The infrared light pixel in the embodiment of the presenttechnology receives infrared light emitted from an infrared lightemitting unit 60 which will be described later and reflected by thesubject and generates an infrared light signal. By measuring a timeperiod from emission of the infrared light to reception of the infraredlight, a distance to the subject is measured. The infrared light pixelcorresponds to the above-mentioned distance measurement pixel(hereinafter, referred to as a Z pixel). A configuration of thesolid-state imaging apparatus 20 and details of distance measurementwill be described later.

The signal processing unit 30 processes the image signal output from thesolid-state imaging apparatus 20. The signal processing unit 30separates the image signal output from the solid-state imaging apparatus20 into a visible light signal and an infrared light signal and outputsthe visible light signal and the infrared light signal respectively tothe image processing unit 40 and the distance measurement unit 50.Further, the signal processing unit 30 also controls the solid-stateimaging apparatus 20.

The image processing unit 40 performs image processing on the visiblelight signal output from the signal processing unit 30. As the imageprocessing, for example, de-mosaic processing for interpolating signalsof other lacking color with respect to a unicolor visible light signalgenerated by the solid-state imaging apparatus 20, processing ofconverting a visible light signal into a luminance signal and a colordifference signal, or the like, can be performed. The image signalprocessed by the image processing unit 40 is, for example, output tooutside the imaging system 1 by way of a signal line (which is notillustrated).

The distance measurement unit 50 measures a distance to the subject onthe basis of the infrared light signal output from the signal processingunit 30. Further, the distance measurement unit 50 also controls theinfrared light emitting unit 60.

The infrared light emitting unit 60 emits infrared light to the subjecton the basis of control by the distance measurement unit 50.

Configuration of Solid-State Imaging Apparatus

FIG. 2 is a diagram illustrating a configuration example of asolid-state imaging apparatus 20 in the embodiment of the presenttechnology. The solid-state imaging apparatus 20 includes a pixel arrayunit 100, a vertical driving unit 200, a horizontal transferring unit300, and an analog digital converter (ADC) 400.

The pixel array unit 100 includes a visible light pixel, an infraredlight pixel and a signal generating unit, which are arranged in atwo-dimensional array. These visible light pixel and infrared lightpixel respectively include photoelectric converting units which generateelectric charges in accordance with visible light and infrared light.Further, the signal generating unit converts the electric chargesgenerated by the photoelectric converting units into an image signal ata predetermined timing and outputs the image signal. After photoelectricconversion is performed for a predetermined period, by generating animage signal based on the electric charges generated through thephotoelectric conversion, it is possible to perform exposure. FIG. 2illustrates an example where, in the pixel array unit 100, one signalgenerating unit 150 is disposed for four pixels (pixels 110, 120, 130and 140). In this case, electric charges generated at the pixels 110,120, 130 and 140 are transferred to the signal generating unit 150, andan image signal based on these electric charges is output. An imagesignal based on the electric charge generated by the visible light pixelamong these pixels is output as a visible light signal, and an imagesignal based on the electric charge generated by the infrared lightpixel is generated as an infrared light signal.

A signal, or the like, for controlling selection of the above-describedpixels is transmitted through a signal line 101. Further, the imagesignal output from the signal generating unit 150 is transmitted througha signal line 102. These signal lines 101 and 102 are wired in an XYmatrix in the pixel array unit 100. That is, one signal line 101 iscommonly wired to a pixel 110, or the like, disposed on the same row,and output of the pixel 110, or the like, disposed on the same column iscommonly wired to one signal line 102.

The vertical driving unit 200 generates a control signal and outputs thecontrol signal to the pixel array unit 100. The vertical driving unit200 outputs the control signal to all the signal lines 101 of the pixelarray unit 100. The control signal output from the vertical driving unit200 includes a signal for controlling transfer of the electric chargegenerated at the above-described pixel 110, or the like, to the signalgenerating unit 150, and a signal for controlling generation of an imagesignal at the signal generating unit 150.

The horizontal transferring unit 300 performs processing on the imagesignal output from the pixel array unit 100. An output signalcorresponding to a pixel 110, or the like, corresponding to one row ofthe pixel array unit 100 is input to the horizontal transferring unit300 at the same time. The horizontal transferring unit 300 performsparallel-serial conversion on the input image signal and outputs theconverted image signal.

The analog digital converter 400 converts (AD converts) the image signaloutput from the horizontal transferring unit 300 from an analog signalto a digital signal. The AD converted image signal is output to outsidethe solid-state imaging apparatus 20 via an output buffer (notillustrated).

Circuit Configuration of Pixel

FIG. 3 is a diagram illustrating a configuration example of a pixel inthe first embodiment of the present technology. FIG. 3 illustrates acircuit configuration of pixels 110, 120, 130 and 140, the signalgenerating unit 150 and the electric charge holding unit 151.

The pixel 110 includes a photoelectric converting unit 111, an electriccharge transferring unit 113 and an over flow drain 112. Note that theelectric charge transferring unit 113 and the over flow drain 112 areconfigured with metal oxide semiconductor (MOS) transistors.

In addition to the signal line 101, a power line Vdd and a groundingwire are connected to the pixel 110. Power supply of the pixel 110 issupplied via the power line Vdd and the grounding wire. Further, thesignal line 101 is configured with a plurality of signal lines (OFD1 andTR1). The over flow drain 1 (OFD1) is a signal line for transmitting acontrol signal to the over flow drain 112. The transfer 1 (TR1) is asignal line for transmitting a control signal to the electric chargetransferring unit 113. As illustrated in FIG. 3, all of these areconnected to a gate of a MOS transistor. When a voltage which is equalto or greater than a threshold between a gate and a source (hereinafter,referred to as an ON signal) is input through these signal lines, thecorresponding MOS transistor becomes conductive.

As illustrated in FIG. 3, an anode of the photoelectric converting unit111 is grounded, and a cathode is grounded to a source of the electriccharge transferring unit 113 and a source of the over flow drain 112. Agate and a drain of the over flow drain 112 are respectively connectedto the OFD1 and Vdd. A gate of the electric charge transferring unit 113is connected to the signal line TR1, and a drain is connected to one endof the electric charge holding unit 151.

The photoelectric converting unit 111 generates and accumulates electriccharges in accordance with a light receiving amount. The photoelectricconverting unit 111 is configured with a photodiode. One of the visiblelight converting unit for visible light and the infrared lightconverting unit for infrared light corresponds to the photoelectricconverting unit 111. As will be described later, it is possible toconstitute the visible light converting unit or the infrared lightconverting unit by changing characteristics of a color filter disposedfor each pixel.

The electric charge transferring unit 113 transfers the electric chargegenerated by the photoelectric converting unit 111 to the electriccharge holding unit 151. The electric charge transferring unit 113transfers the electric charge by conducting electricity between thephotoelectric converting unit 111 and the electric charge holding unit151.

The over flow drain 112 discharges the electric charge generated by thephotoelectric converting unit 111. The over flow drain 112 dischargesthe electric charge excessively generated at the photoelectricconverting unit 111. Further, by conducting electricity between thephotoelectric converting unit 111 and the Vdd, it is also possible todischarge all the electric charges accumulated in the photoelectricconverting unit 111.

The pixel 120 includes a photoelectric converting unit 121, an electriccharge transferring unit 122 and an over flow drain 123.

The signal line 101 connected to the pixel 120 is configured with aplurality of signal lines (an OFD2 and a TR2). The over flow drain 2(OFD2) is a signal line for transmitting a control signal to the overflow drain 123. The transfer 2 (TR2) is a signal line for transmitting acontrol signal to the electric charge transferring unit 122. The OFD2and the TR2 are respectively connected to gates of the over flow drain123 and the electric charge transferring unit 122. Because otherconfiguration of the pixel 120 is similar to that of the pixel 110,description will be omitted.

The pixel 130 includes a photoelectric converting unit 131, an electriccharge transferring unit 133 and an over flow drain 132.

The signal line 101 connected to the pixel 130 is configured with aplurality of signal lines (an OFD3 and a TR3). The over flow drain 3(OFD3) is a signal line for transmitting a control signal to the overflow drain 132. The transfer 3 (TR3) is a signal line for transmitting acontrol signal to the electric charge transferring unit 133. The OFD3and the TR3 are respectively connected to gates of the over flow drain132 and the electric charge transferring unit 133. Because otherconfiguration of the pixel 130 is similar to that of the pixel 110,description will be omitted.

The pixel 140 includes a photoelectric converting unit 141, an electriccharge transferring unit 142 and an over flow drain 143.

The signal line 101 connected to the pixel 140 is configured with aplurality of signal lines (an OFD4 and a TR4). The over flow drain 4(OFD4) is a signal line for transmitting a control signal to the overflow drain 143. The transfer 4 (TR4) is a signal line for transmitting acontrol signal to the electric charge transferring unit 142. The OFD4and the TR4 are respectively connected to gates of the over flow drain143 and the electric charge transferring unit 142. Because otherconfiguration of the pixel 140 is similar to that of the pixel 110,description will be omitted.

The electric charge holding unit 151 holds the electric chargestransferred from the pixels 110, 120, 130 and 140.

The signal generating unit 150 generates a signal in accordance with thesignal held in the electric charge holding unit 151. The signalgenerating unit 150 includes MOS transistors 152 to 154.

The signal line 101, the signal line 102, the power line Vdd and thegrounding wire are connected to the signal generating unit 150. Thesignal line 101 is configured with a plurality of signal lines (an RSTand an SEL). The reset (RST) is a signal line for transmitting a controlsignal to the MOS transistor 152. The select (SEL) is a signal line fortransmitting a control signal to the MOS transistor 154. The signal line102 is a signal line for transmitting a signal generated by the signalgenerating unit 150.

As illustrated in FIG. 3, drains of the MOS transistors 152 and 153 areconnected to the Vdd. A source of the MOS transistor 152 and a gate ofthe MOS transistor 153 are connected to one end of the electric chargeholding unit 151 to which drains of the above-mentioned electric chargetransferring units 113, 122, 133 and 142 are connected. The other end ofthe electric charge holding unit 151 is grounded. A source of the MOStransistor 153 is connected to a drain of the transistor 154, and asource of the MOS transistor 154 is connected to the signal line 102.Gates of the MOS transistor 152 and the MOS transistor 154 arerespectively connected to the signal lines RST and SEL.

The MOS transistor 153 is a MOS transistor which generates a signal inaccordance with the electric charge held in the electric charge holdingunit 151. The MOS transistor 154 is a MOS transistor which outputs thesignal generated by the MOS transistor 153 to the signal line 102 as animage signal. Note that a constant current power supply which is notillustrated is connected to the signal line 102, and constitutes asource follower circuit with the MOS transistor 153. The constantcurrent power supply is disposed in the horizontal transferring unit 300described with reference to FIG. 2.

The MOS transistor 152 is a MOS transistor which discharges the electriccharge held in the electric charge holding unit 151. The MOS transistor152 discharges the electric charge by conducting electricity between theelectric charge holding unit 151 and the Vdd.

Operation at Pixel

Operation of the pixel illustrated in FIG. 3 will be described using anexample of the pixel 110. First, when an ON signal is input from an OFG,the over flow drain 112 becomes conductive, and the Vdd is applied to acathode of the photoelectric converting unit 111. By this means, theelectric charge accumulated in the photoelectric converting unit 111 isdischarged. Then, an electric charge in accordance with the lightreceiving amount is newly generated and accumulated in the photoelectricconverting unit 111.

When an ON signal is input from the TR1 after a predetermined exposureperiod has elapsed, the electric charge transferring unit 113 becomesconductive. By this means, a state between the photoelectric convertingunit 111 and the electric charge holding unit 151 becomes a conductivestate, and the electric charge accumulated in the photoelectricconverting unit 111 is transferred to the electric charge holding unit151 and held. Because the gate of the MOS transistor 153 is connected tothe electric charge holding unit 151, a signal based on the electriccharge held in the electric charge holding unit 151 is generated. Inthis event, if the ON signal is input from the SEL, the MOS transistor154 becomes conductive, and a signal generated by the MOS transistor 153is output to the signal line 102.

Then, when the ON signal is input from the RST and the MOS transistor152 becomes conductive, the Vdd is applied to the electric chargeholding unit 151, and the held electric charge is discharged.

Sources of the electric charge transferring units 113, 122, 133 and 142are commonly connected to the electric charge holding unit 151.Therefore, by controlling the TR1 to the TR4 which control the electriccharge transferring units 113, 122, 133 and 142, it is possible togenerate and output an image signal based on the electric chargegenerated at a desired pixel among the pixels 110, 120, 130 and 140.

As described above, the operation of each pixel is not different fromeach other. However, by changing characteristics of the photoelectricconverting units (photoelectric converting units 111, 121, 131 and 141),it is possible to use each pixel as a visible light pixel or an infraredlight pixel. Specifically, by changing a color filter disposed at eachpixel, it is possible to change characteristics of the photoelectricconverting unit. This color filter is a filter which selects light to beincident on the photoelectric converting unit. By disposing a colorfilter which transmits only visible light, it is possible to make thephotoelectric converting unit a visible light converting unit whichdeals with visible light and make a pixel having the visible lightconverting unit a visible light pixel. Meanwhile, in the case where acolor filter which transmits only infrared light is disposed, it ispossible to make the photoelectric converting unit an infrared lightconverting unit which deals with infrared light and make a pixel havingthe infrared light converting unit an infrared light pixel. Dispositionof the color filter will be described in detail later.

Here, combination of one electric charge holding unit and a plurality ofphotoelectric converting units commonly connected to the electric chargeholding unit will be referred to as a converting block. In FIG. 3, anexample is illustrated where the electric charge holding unit 151 andfour photoelectric converting units (photoelectric converting units 111,121, 131 and 141) constitute the converting block. Among the convertingblocks, a converting block configured with a plurality of visible lightconverting units will be referred to as a visible light convertingblock. Further, a converting block configured with a plurality ofinfrared light converting units will be referred to as an infrared lightconverting block. Still further, the electric charge holding unit in thevisible light converting block will be referred to as a visible lightelectric charge holding unit, and the electric charge holding unit inthe infrared light converting block will be referred to as an infraredlight electric charge converting unit. As will be described later, thevisible light electric charge holding unit exclusively holds electriccharges respectively generated by a plurality of visible lightconverting units in different periods. On the other hand, the infraredlight electric charge holding unit collectively holds the electriccharges respectively generated by a plurality of infrared lightconverting units at the same time. The signal generating unit 150 whichgenerates a signal in accordance with the electric charge held in theinfrared light electric charge holding unit will be referred to as aninfrared light signal generating unit.

Arrangement of Pixels

FIG. 4 is a diagram illustrating an arrangement example of pixels in thefirst embodiment of the present technology. FIG. 4 is a plan view inwhich four converting blocks are arranged. Further, description will beprovided while an upper left converting block in FIG. 4 is associatedwith pixels, or the like, described with reference to FIG. 3. However,description will be omitted for the over flow drains 112, 123, 132 and143. As illustrated in FIG. 4, the electric charge holding unit 151 isdisposed at the center of the pixels 110, 120, 130 and 140. The electriccharge transferring units 113, 122, 133 and 142 of the respective pixelsare respectively disposed adjacent to the electric charge holding unit151, and the photoelectric converting units 111, 121, 131 and 141 aredisposed adjacent to these electric charge transferring units. Thesignal generating unit 150 is disposed adjacent to each of theseconverting blocks. If the photoelectric converting units 111, 121, 131and 141 illustrated in FIG. 4 are irradiated with light from thesubject, photoelectric conversion is performed. That is, in thephotoelectric converting unit 111, or the like, an area illustrated inFIG. 4 corresponds to a light receiving face on which visible light, orthe like, is received.

Further, color filters 119, 129, 139 and 149 are respectively disposedat the pixels. Characters of R, G, B and Z described at the respectivepixels indicate types of the color filters. Here, color filters 129 and149 of the pixels 120 and 140 at which a character of Z is described arecolor filters which transmit infrared light. Therefore, thephotoelectric converting units 111 and 131 and 161, 171, 181 and 191 ina lower left converting block in FIG. 4 correspond to the visible lightconverting units, and the pixels 110, 130, 160, 170, 180 and 190 havingthese correspond to visible light pixels. Meanwhile, the photoelectricconverting units 121 and 141 correspond to infrared light convertingunits, and the pixels 120 and 140 having these correspond to infraredlight pixels. As is clear from FIG. 4, a light receiving face of theinfrared light converting unit has substantially the same size as thesize of the light receiving face of the visible light converting unit.

Further, an upper left converting block in FIG. 4 includes two infraredlight converting units (the photoelectric converting units 121 and 141),two visible light converting units (the photoelectric converting units111 and 131) and the infrared light electric charge holding unit (theelectric charge holding unit 151), and corresponds to the infrared lightconverting block. Further, the signal generating unit 150 disposedadjacent to this converting block corresponds to the infrared lightsignal generating unit which generates a signal in accordance with theelectric charge held in the infrared light electric charge holding unit(the electric charge holding unit 151). In a similar manner, an upperright converting block in FIG. 4 also corresponds to the infrared lightconverting block. Meanwhile, a lower left converting block in FIG. 4includes four visible light converting units (the photoelectricconverting units 161, 171, 181 and 191) and the visible light electriccharge holding unit (the electric charge holding unit 159), andcorresponds to the visible light converting block. In a similar manner,a lower right converting block in FIG. 4 also corresponds to the visiblelight converting block. In this visible light converting block, R, G andB pixels are disposed in a Bayer array.

Cross-Section of Pixel

FIG. 5 is a schematic diagram illustrating a configuration example ofthe pixel in the first embodiment of the present technology. FIG. 5 is across-section diagram along line A-A′ in FIG. 4. Description will beprovided using an example of the pixels 110 and 140. The photoelectricconverting units 111 and 141 in FIG. 5 are respectively configured witha p-type semiconductor region 517 and n-type semiconductor regions 511and 512 embedded inside the p-type semiconductor region 517.Photoelectric conversion is performed at a pn junction formed atinterface of these semiconductor regions, and an electric charge inaccordance with a light receiving amount is generated. In this event, anelectron among the generated electric charge is accumulated in then-type semiconductor regions 511 and 512. The color filter 119 or 149, aflattening film 503, and a micro lens 501 are sequentially disposed overthe photoelectric converting unit. The flattening film 503 flattens asurface of the pixel. The micro lens 501 is a lens which makes lightradiated to the pixel focus on the photoelectric converting unit. Alight shielding film 502 is disposed between the color filters 119 and149. The light shielding film 502 shields light obliquely incident fromthe adjacent pixels.

Further, a separating region 513 is disposed between pixels in thep-type semiconductor region 517. The separating region 513 is a regionwhich separates the pixels and shields light obliquely incident from theadjacent pixels. The electric charge holding unit 151 is disposed at anintermediate portion of the pixel 110 and the pixel 140. The electriccharge holding unit 151 is configured with the n-type semiconductorregion 514. The n-type semiconductor region 514 is a region which isreferred to as a floating diffusion (FD), and to which the signalgenerating unit 150 (not illustrated) is connected. As illustrated inFIG. 5, because the electric charge holding unit 151 is disposedimmediately below the separating region 513, light is shielded by theseparating region 513. The electric charge transferring units 113 and142 are disposed between the electric charge holding unit 151 and thephotoelectric converting units 111 and 141. Gate electrodes 515 and 516are respectively disposed at the electric charge transferring units 113and 142. When an ON voltage is applied to the gate electrodes, thep-type semiconductor region 517 between the photoelectric convertingunit 111 or 141 and the electric charge holding unit 151 becomesconductive, and the electric charge transferring units 113 and 142become conductive.

An interlayer insulating layer 519 and a wiring layer 518 are disposedbelow the p-type semiconductor region 517. The wiring layer 518transmits signals of the pixels 110 and 140 and constitutes the signallines 101 and 102 described with reference to FIG. 3. The interlayerinsulating layer 519 insulates the wiring layers 518 from each other.

In this manner, because light to the electric charge holding unit 151 inFIG. 5 is shielded by the separating region 513, a dark current isreduced.

Principle of Distance Measurement

FIG. 6 is a diagram illustrating a distance measurement method in thefirst embodiment of the present technology. The emitted infrared lightin FIG. 6 has a waveform of infrared light emitted from the infraredlight emitting unit 60. Further, the reflected infrared light has awaveform of infrared light obtained by the emitted infrared light beingreflected by the subject and incident on the solid-state imagingapparatus 20. A Z pixel of the solid-state imaging apparatus 20 receivesthe reflected infrared light, converts the reflected infrared light intoan infrared light signal and performs exposure. In this event, aninfrared light signal is generated while different exposure periods areset using two Z pixels. A first exposure period and a second exposureperiod indicate relationship of the exposure periods set for the two Zpixels, and a period of a binarized value “1” of the waveformcorresponds to the exposure period.

As illustrated in FIG. 6, a pulse width of the emitted infrared light ismodulated to 50% duty and the emitted infrared light is emitted from theinfrared light emitting unit 60. Meanwhile, the reflected infrared lighthas a waveform in which a phase is delayed with respect to the emittedinfrared light. D in FIG. 6 indicates the delay of the phase. Thiscorresponds to a time period from when the emitted infrared light isreflected by the subject until when the emitted infrared light reachesthe solid-state imaging apparatus 20. By measuring this time period, itis possible to calculate a distance to the subject.

As the first exposure period in FIG. 6, an exposure period insynchronization with the emitted infrared light is set. Meanwhile, asthe second exposure period, an exposure period in which a phase isshifted by 180° with respect to the emitted infrared light is set. Inthe first exposure period, photoelectric conversion is performed onreflected light in a period 701 in FIG. 6. In the second exposureperiod, photoelectric conversion is performed on reflected light in aperiod 702 in FIG. 6. A ratio of the period 701 and the period 702changes on the basis of the delay of the phase. That is, as the phasedelay D becomes larger, the period 701 becomes shorter, and the period702 becomes longer. Therefore, by calculating a ratio of the infraredlight signals generated by the Z pixels in the first exposure period andthe second exposure period, it is possible to calculate the phase delayD.

Here, when the infrared light signals of the Z pixels for which thefirst and the second exposure periods are set are respectively S1 andS2, and a cycle of the emitted infrared light is T, D can be calculatedusing the following equation.

D=S2×(S1+S2)×T/2

A distance L to the subject can be calculated using the followingequation.

L=D×c/2  (equation 1)

where c is light speed. For example, in the case where a distance to thesubject is 10 m, D is approximately 33 ns. In this case, by setting Tat, for example, 100 ns (a modulation frequency of the emitted infraredlight is 10 MHz), it is possible to measure the distance. Control ofoutput of the pulse-modulated infrared light to the infrared lightemitting unit 60 and calculation of the distance are performed by thedistance measurement unit 50 described with reference to FIG. 1.

In this manner, it is possible to calculate a distance to the subject byusing two Z pixels. Note that, because the reflected infrared lightattenuates in the process of propagation, it is necessary to improve alevel of the infrared light signal by repeatedly emitting infrared lightand accumulating the electric charges generated by the Z pixels.

Operation of Solid-State Imaging Apparatus

FIG. 7 is a diagram illustrating the infrared light converting block inthe first embodiment of the present technology. Arrangement of thepixels in FIG. 7 is similar to arrangement of the pixels described withreference to FIG. 4. A distance is measured by a pixel group 660 formedwith Z pixels (Za, Zb, Zc and Zd) disposed in two infrared lightconverting blocks 620 and 630 at an upper side in FIG. 7. Za and Zc, andZb and Zd belong to different infrared light converting blocks, and areconnected to different infrared light electric charge holding units 621and 631. A distance is measured by applying the first exposure periodand the second exposure period descried with reference to FIG. 6 to Zaand Zc, and Zb and Zd. Meanwhile, the visible light converting block 610in FIG. 7 includes a visible light electric charge holding unit 611. Thevisible light converting block 610 is provided for performing imagingusing visible light.

FIG. 8 is a diagram illustrating relationship between an imaging periodand a distance measurement period in the first embodiment of the presenttechnology. As illustrated in FIG. 8, the solid-state imaging apparatus20 measures a distance to the subject after performing imaging forgenerating an image signal of the subject. The imaging period and thedistance measurement period which are periods during which imaging anddistance measurement are performed are alternately repeated. In theimaging period, reset, exposure and signal output are sequentiallyexecuted in the visible light pixel starting from a first line. Here,reset is discharging of the electric charge accumulated in the electriccharge converting unit. Reset is performed on all the pixels included inone line, and exposure is started. After a predetermined exposure periodhas elapsed, an image signal based on the electric charge generatedthrough photoelectric conversion is generated and output. By this means,exposure in the line is finished. A frame which is an image signalcorresponding to one screen can be obtained by performing these on allthe lines. Then, the period shifts to the distance measurement period.

In the distance measurement period, reset, exposure and signal outputare sequentially executed in the infrared light pixel starting from afirst line. In this event, an infrared light signal for distancemeasurement is generated and output.

Imaging Method

FIG. 9 is a diagram illustrating an imaging method in the firstembodiment of the present technology. FIG. 9 illustrates an imagingmethod at a visible light converting block 610 and illustratesrelationship between an input signal and an output signal. The signalsillustrated in FIG. 9 correspond to the signals described with referenceto FIG. 3. Among these signals, in the input signal, a period in which avalue of binarized waveform “1” corresponds to input of an ON signal.Further, description will be provided using reference numerals ofcomponents (such as the electric charge transferring unit and the overflow drain) which are the same reference numerals as those of thecomponents described with reference to FIG. 3, other than the visiblelight electric charge holding unit 611.

First, ON signals are input to the OFD1 to OFD4 to make the over flowdrains 112 123, 132 and 143 conductive (T1). By this means, electriccharges accumulated in the photoelectric converting units 111, 121, 131and 141 are discharged, and reset is executed. After reset is finished,input of the ON signals to the OFD1 to OFD4 is stopped to make the overflow drains 112, 123, 132 and 143 non-conductive (T2). By this means,electric charges obtained by photoelectric conversion are newlygenerated and accumulated in the photoelectric converting units 111,121, 131 and 141. That is, exposure is started.

After a predetermined exposure period has elapsed, an ON signal is inputto the RST to make the MOS transistor 152 of the signal generating unit150 conductive (T3). By this means, the electric charge in the visiblelight electric charge holding unit 611 is discharged. At the same time,an ON signal is input to the SEL to make the MOS transistor 154 of thesignal generating unit 150 conductive. By this means, when an electriccharge is transferred to and held in the visible light electric chargeholding unit 611 in subsequent operation, a visible light signal basedon this electric charge is output to the signal line 102.

Subsequently, input of the ON signal to the RST is stopped to make theMOS transistor 152 non-conductive, and an ON signal is input to the TR1to make the electric charge transferring unit 113 of the pixel 110conductive (T4). By this means, the electric charge accumulated in thephotoelectric converting unit 111 is transferred to the visible lightelectric charge holding unit 611. Further, a signal “G” based on theelectric charge transferred to the visible light electric charge holdingunit 611 is output to the signal line 102. The signal corresponds to avisible light signal at the pixel 110 (an image signal corresponding togreen light). An exposure period at the pixel 110 is stopped by theelectric charge accumulated in the photoelectric converting unit 111being transferred to the visible light electric charge holding unit 611,and the processing shifts to signal output described with reference toFIG. 8.

Subsequently, input of the ON signal to the TR1 is stopped, and an ONsignal is input to the RST (T5). By this means, the electric charge heldin the visible light electric charge holding unit 611 is discharged, andsignal output at the pixel 110 is finished.

Subsequently, input of the ON signal to the RST is stopped, and an ONsignal is input to the TR2 to make the electric charge transferring unit122 of the pixel 120 conductive (T6). By this means, the electric chargeaccumulated in the photoelectric converting unit 121 is transferred tothe visible light electric charge holding unit 611, and a signal “B”based on the transferred electric charge is output to the signal line102. This signal corresponds to a visible light signal (an image signalcorresponding to blue light) in the pixel 120. Then, input of the ONsignal to the TR2 is stopped, and an ON signal is input to the RST (T7).By this means, the electric charge in the visible light electric chargeholding unit 611 is discharged and signal output at the pixel 120 isfinished.

Subsequently, input of the ON signal to the RST is stopped, and an ONsignal is input to the TR3 to make the electric charge transferring unit133 of the pixel 130 conductive (T8). By this means, the electric chargeaccumulated in the photoelectric converting unit 131 is transferred tothe visible light electric charge holding unit 611, and a signal “R”based on the transferred electric charge is output to the signal line102. This signal corresponds to a visible light signal (an image signalcorresponding to red light) at the pixel 130. Then, input of the ONsignal to the TR3 is stopped, and an ON signal is input to the RST (T9).By this means, the electric charge of the visible light electric chargeholding unit 611 is discharged, and signal output at the pixel 130 isfinished.

Subsequently, input of the ON signal to the RST is stopped, and an ONsignal is input to the TR4 to make the electric charge transferring unit142 of the pixel 140 conductive (T10). By this means, the electriccharge accumulated in the photoelectric converting unit 141 istransferred to the visible light electric charge holding unit 611, and asignal “G” based on the transferred electric charge is output to thesignal line 102. This signal corresponds to a visible light signal (animage signal corresponding to green light) at the pixel 140. Then, inputof the ON signals to the TR4 and the SEL is stopped (T11). By thismeans, signal output at the pixel 140 is finished.

After processing described with reference to FIG. 9 is performed on alllines, an imaging period for one screen is finished. In this manner, inthe visible light converting block 610, electric charges respectivelygenerated by the four photoelectric converting units 111, 121, 131 and141 are exclusively held in the visible light electric charge holdingunit 611 in different periods (T4, T6, T8 and T10). That is, electriccharges respectively generated by a plurality of visible lightconverting units are exclusively held in the visible light electriccharge holding unit.

Distance Measurement

FIG. 10 is a diagram illustrating a distance measurement method in thefirst embodiment of the present technology. FIG. 10 illustrates adistance measurement method in a pixel group 660. FIG. 10 illustratesrelationship among an input signal at a Z pixel of the pixel group 660,emitted infrared light, reflected infrared light, and held electriccharge amounts at the infrared light electric charge holding units 621and 631. Note that the signals of the infrared light converting blocks620 and 630 described with reference to FIG. 7 correspond to signalsdescribed with reference to FIG. 3. That is, among the Z pixels of thepixel group 660, signals of Za and Zc respectively correspond to signalsat the pixels 120 and 140 in FIG. 3. In a similar manner, signals of Zband Zd respectively correspond to signals at the pixels 110 and 130 inFIG. 3. Description will be provided using reference numerals ofcomponents which are the same reference numerals as those of thecomponents described with reference to FIG. 3, other than the infraredlight electric charge holding units 621 and 631.

First, ON signals are input to the RSTs of the infrared light convertingblocks 620 and 630 to make the MOS transistor 152 conductive. At thesame time, ON signals are input to the OFD2 and the OFD4 of the infraredlight converting block 620 and the OFD1 and the OFD3 of the infraredlight converting block 630 to make the over flow drains 123, 143, 112and 132 conductive (T1). By this means, the electric charges held in theinfrared light electric charge holding units 621 and 631 are discharged.Further, the electric charges accumulated in the photoelectricconverting units 121 and 141 of the infrared light converting block 620and the photoelectric converting units 111 and 131 of the infrared lightconverting block 630 are discharged, and reset is performed. After resetis finished, the above-described input of the ON signals to the RST andthe OFD is finished (T2).

Subsequently, infrared light is emitted from the infrared light emittingunit 60, ON signals are input to the TR2 and the TR4 of the infraredlight converting block 620, and ON signals are input to the OFD1 and theOFD3 of the infrared light converting block 630 (T3). By this means, inthe infrared light converting block 620, the electric chargetransferring units 122 and 142 become conductive, and electric chargesgenerated on the basis of reflected infrared light at the photoelectricconverting units 121 and 141 are held in the infrared light electriccharge holding unit 621. Meanwhile, in the infrared light convertingblock 630, the over flow drains 112 and 132 become conductive, and thephotoelectric converting units 111 and 131 are reset.

Subsequently, emission of infrared light from the infrared lightemitting unit 60 is stopped, and input of the ON signals to the TR2 andthe TR4 of the infrared light converting block 620 and the OFD1 and theOFD3 of the infrared light converting block 630 is stopped. At the sametime, ON signals are input to the OFD1 and the OFD3 of the infraredlight converting block 620 and the TR2 and the TR4 of the infrared lightconverting block 630 (T4). By this means, in the infrared lightconverting block 620, the over flow drains 123 and 143 becomeconductive, and the photoelectric converting units 121 and 141 arereset. Meanwhile, in the infrared light converting block 630, theelectric charge transferring units 113 and 133 become conductive, andelectric charges generated on the basis of reflected infrared light atthe photoelectric converting units 111 and 131 are held in the infraredlight electric charge holding unit 631.

Subsequently, input of the ON signals to the OFD1 and the OFD3 of theinfrared light converting block 620 and the TR2 and the TR4 of theinfrared light converting block 630 is stopped (T5). Thereafter,operation of T3 and T4 is repeated the predetermined number of times. Bythis means, electric charges based on reflected infrared light areaccumulated in the infrared light electric charge holding units 621 and631.

Subsequently, ON signals are input to the SELs of the infrared lightconverting blocks 620 and 630 (T6). By this means, the MOS transistors154 of the infrared light converting blocks 620 and 630 becomeconductive, and infrared light signals based on the electric chargesheld in the infrared light electric charge holding units 621 and 631 arerespectively output. Then, input of the ON signals to the SELs of theinfrared light converting blocks 620 and 630 is stopped, and thedistance measurement period is finished (T7).

As described above, photoelectric conversion in synchronization withemitted infrared light is performed at the Za and the Zc of the infraredlight converting block 620. That is, the first exposure period describedwith reference to FIG. 6 is set at the Za and the Zc. Meanwhile, in theZb and the Zd of the infrared light converting block 630, photoelectricconversion is performed in a period in which a phase is shifted by 180°with respect to the emitted infrared light. That is, the second exposureperiod described with reference to FIG. 6 is applied to the Zb and theZd. The distance measurement unit 50 calculates a distance to thesubject on the basis of the infrared light signals from these Z pixels.

In this manner, in the infrared light converting block 620, the electriccharge transferring units 122 and 142 become conductive at the sametime, and electric charges respectively generated by the twophotoelectric converting units 121 and 141 are collectively held in theinfrared light electric charge holding unit 621 at the same time (T3).In a similar manner, in the infrared light converting block 630, theelectric charge transferring units 113 and 133 become conductive at thesame time, and electric charges respectively generated by the twophotoelectric converting units 111 and 131 are collectively held in theinfrared light electric charge holding unit 631 at the same time (T4).That is, electric charges respectively generated by a plurality ofinfrared light converting units are collectively held in the infraredlight electric charge holding unit at the same time. Note that theelectric charge transferring units 122 and 142 are an example of aninfrared light electric charge transferring unit recited in the claims.

Meanwhile, in the G pixel and the R pixel of the infrared lightconverting block 620, a visible light signal is generated by the imagingmethod described with reference to FIG. 9 being applied. That is,electric charges respectively generated by the visible light convertingunits included in these pixels are exclusively held in the infraredlight electric charge holding unit 621 in different periods. Electriccharges are similarly held also in the B pixel and the G pixel of theinfrared light converting block 630.

Distance Measurement Procedure

FIG. 11 is a diagram illustrating an example of distance measurementprocessing procedure in the first embodiment of the present technology.The processing in FIG. 11 is executed in the imaging system 1 when adistance is measured. Procedure of the processing will be describedusing symbols illustrated in FIG. 7.

First, the infrared light emitting unit 60 emits infrared light to thesubject (step S901). Then, exposure of infrared light is performed bythe infrared light converting block 620 for which the first exposureperiod is set (step S902). After a predetermined exposure period haselapsed, the electric charge generated by the exposure is held in theinfrared light electric charge holding unit 621 (step S903). Emission ofthe infrared light by the infrared light emitting unit 60 is stopped(step S904). Then, exposure of infrared light is performed by theinfrared light converting block 630 for which the second exposure periodis set (step S905), and the generated electric charge is held in theinfrared light electric charge holding unit 631 (step S906). Then, it isjudged whether or not the number of times of exposure reaches apredetermined number of times of exposure (step S907). In the case wherethe number of times of exposure does not reach the predetermined numberof times of exposure (step S907: No), processing from step S901 isexecuted again.

On the other hand, in the case where the number of times of exposurereaches the predetermined number of times of exposure (step S907: Yes),an infrared light signal based on the electric charges held in theinfrared light electric charge holding units 621 and 631 is generated(step S908). Finally, the distance measurement unit 50 calculates adistance on the basis of the generated infrared light signal (stepS909).

In the first embodiment of the present technology, as described withreference to FIG. 7, exposure is performed while the first exposureperiod and the second exposure period are respectively set at the Za andthe Zc, and the Zb and the Zd of the pixel group 660. By this means,infrared light signals based on the first exposure period and the secondexposure period can be acquired at the same time, so that it is possibleto shorten the distance measurement period. Further, by performingphotoelectric conversion using two infrared light converting units whichhave light receiving faces having the same size as that of the lightreceiving face of the visible light converting unit in the visible lightpixel, and which are apparently connected in parallel, it is possible toimprove sensitivity of the infrared light converting unit, because thesensitivity of the photoelectric converting unit, that is, an electriccharge generation amount per unit time is proportional to the lightreceiving area of the photoelectric converting unit.

It is also possible to improve the sensitivity by constituting theinfrared light converting unit having double the area of that of thevisible light converting unit. However, there is a problem that it takesmore time to transfer an electric charge by the electric chargetransferring unit in the photoelectric converting unit having a largearea. In the n-type semiconductor region 512 of the photoelectricconverting unit 141 described with reference to FIG. 5, accumulatedelectric charges are transferred mainly through diffusion of theelectric charges. On the other hand, in the first embodiment of thepresent technology, as described above, two infrared light convertingunits each of which has a light receiving face having the same size asthat of the light receiving face of the visible light converting unit inthe visible light pixel are used, so that it is possible to make thelength of time required for transferring the electric charge the same asthat in the visible light converting unit.

Further, the infrared light converting blocks 620 and 630 in FIG. 7 aredisposed adjacent to each other. Therefore, infrared light signalsgenerated by these infrared light converting blocks can be regarded asinfrared light signals based on the same subject. It is possible toimprove accuracy of distance measurement compared to a case where theinfrared light converting blocks 620 and 630 are disposed away from eachother.

Further, the visible light converting block is configured with fourvisible light pixels and is configured in a Bayer array. Meanwhile, thepixel group 660 in the first embodiment of the present technology isalso configured with four Z pixels. By this means, it is possible tosimplify arrangement of Z pixels in the pixel array unit 100. Thesolid-state imaging apparatus 20 is configured by replacing the visiblelight pixels of the pixel array unit 100 with infrared light pixels. Inthis event, because the number of the visible light converting blocks isthe same as the number of pixel groups 660 formed with Z pixels, it ispossible to replace the visible light pixels with the infrared lightpixels without changing a ratio of R pixels, G pixels and B pixels withrespect to the whole of the pixel array unit 100.

Still further, in the first embodiment of the present technology, thesize of the Z pixel is made substantially the same as that of thevisible light pixel. By this means, because it is possible to share aconfiguration of the diffusion layer, a wiring pattern, or the like, inthe semiconductor substrate between the Z pixel and the visible lightpixel except a configuration of a color filter, it is possible tomanufacture the Z pixel and the visible light pixel on the basis of thesame design rule.

In this manner, according to the first embodiment of the presenttechnology, by using two Z pixels having substantially the same size asthat of the visible light pixel in parallel, it is possible to improvesensitivity of the Z pixel. By this means, it is possible to improveaccuracy of distance measurement.

Modified Example

While, in the above-described embodiment, the visible light convertingblock is configured with three pixels of an R pixel, a G pixel and a Bpixel as the visible light pixels, the visible light converting blockmay be configured with four pixels further including a W pixel for whitelight. For example, it is possible to employ a configuration in whichone pixel among two G pixels in a Bayer array is replaced with a Wpixel.

FIG. 12 is a diagram illustrating a visible light converting block in amodified example of the first embodiment of the present technology. InFIG. 12, a pixel where a character of W is described corresponds to a Wpixel, and a color filter which transmits white light is disposed at thepixel. Also in FIG. 12, because the number of the visible lightconverting blocks 611 is the same as the number of pixel groups 660formed with Z pixels, it is possible to replace the visible light pixelswith the infrared light pixels without changing a ratio of the R pixel,the G pixel, the B pixel and the W pixel with respect to the whole pixelarray unit 100.

Second Embodiment

In the above-described embodiment, a distance is measured using theinfrared light converting block configured with two Z pixels and twovisible light pixels. Meanwhile, in the second embodiment of the presenttechnology, a distance is measured using an infrared light convertingblock configured with four Z pixels. By this means, it is possible toreduce the number of signal lines connected to the Z pixels.

Operation of Solid-State Imaging Apparatus

FIG. 13 is a diagram illustrating an infrared light converting block inthe second embodiment of the present technology. The infrared lightconverting block 620 in FIG. 13 is different from the infrared lightconverting block 620 described with reference to FIG. 7 in that all thepixels are configured with Z pixels. That is, the infrared lightconverting block 620 in FIG. 13 employs a configuration where the pixelsgroups 660 formed with Z pixels in FIG. 7 match pixels of the infraredlight converting block 620. Therefore, at Z pixels in the infrared lightconverting block 620 in FIG. 13, the electric charge transferring unitsand the over flow drains can be made to operate at the same time at thefour pixels. Because an infrared light signal is generated using four Zpixels, it is possible to improve sensitivity of the Z pixel, so that itis possible to improve accuracy of distance measurement. Because otherconfiguration of the solid-state imaging apparatus 20 and the imagingsystem 1 except this is similar to that of the solid-state imagingapparatus 20 and the imaging system 1 in the first embodiment of thepresent technology, description will be omitted.

FIG. 14 is a diagram illustrating relationship between an imaging periodand a distance measurement period in the second embodiment of thepresent technology.

The distance measurement period of the second embodiment of the presenttechnology is different from the distance measurement period describedwith reference to FIG. 8 in that a first distance measurement period anda second distance measurement period which are two distance measurementperiods are executed after the imaging period.

Imaging Method

FIG. 15 is a diagram illustrating an imaging method in the secondembodiment of the present technology. The same signal is input to theelectric charge transferring units and the over flow drains of all the Zpixels of the infrared light converting block 620 as mentioned above.Because operation in the first distance measurement period and thesecond distance measurement period in FIG. 15 is similar to operation inthe infrared light converting blocks 620 and 630 described withreference to FIG. 10, description will be omitted.

In this manner, according to the second embodiment of the presenttechnology, by measuring a distance using an infrared light convertingblock configured with four Z pixels, it is possible to use a commonsignal as signals to be supplied to the Z pixels. By this means, it ispossible to reduce the number of signal lines.

Third Embodiment

In the above-described first embodiment, a distance is measured usingthe infrared light converting block configured with two Z pixels and twovisible light converting pixels. Meanwhile, in the third embodiment ofthe present technology, a distance is measured using an infrared lightconverting block configured with one Z pixel and three visible lightconverting pixels. By this means, it is possible to use a distancemeasurement method of a scheme in which exposure of reflected infraredlight is performed in four phases.

Operation of Solid-State Imaging Apparatus

FIG. 16 is a diagram illustrating the infrared light converting block inthe third embodiment of the present technology. The infrared lightconverting blocks 620, 630, 640 and 650 in FIG. 16 are different fromthe infrared light converting blocks 620 and 630 described withreference to FIG. 7 in that each of the infrared converting blocks 620,630, 640 and 650 are configured with one Z pixel and three visible lightconverting pixels. Further, the pixel group 660 formed with Z pixels inFIG. 16 is disposed across these four infrared light converting blocks,and disposed across two lines. Because configurations of the solid-stateimaging apparatus 20 and the imaging system 1 other than this aresimilar to those of the solid-state imaging apparatus 20 and the imagingsystem 1 in the first embodiment of the present technology, descriptionwill be omitted.

Principle of Distance Measurement

FIG. 17 is a diagram illustrating a distance measurement method in thethird embodiment of the present technology. In the distance measurementmethod illustrated in FIG. 17, a distance is measured by emittinginfrared light whose amplitude is modulated with a sine wave andmeasuring a phase delay of reflected infrared light. FIG. 17aillustrates relationship between the emitted infrared light and thereflected infrared light. If the emitted infrared light is indicated ina positive x axis direction in FIG. 17a , the reflected infrared lighthas a waveform of a phase which delays in accordance with the distanceto the subject. If this delay is indicated with φ, φ can be expressedwith the following equation.

φ=tan⁻¹(q/r)

where q is a crest value of a reflective wave, and r indicates a crestvalue of a reflective wave whose phase advances by 90°.

FIG. 17b illustrates a method for acquiring q and r. A crest value ofthe reflected infrared light is measured for each phase of 90° in onecycle of the emitted infrared light. When these are indicated with p1 top4, q and r can be expressed with the following equations.

q=|(p1−p3)/2|

r=|(p2−p4)/2|

In this manner, by calculating respective differences between p1 and p3,and p2 and p4, it is possible to remove influence of infrared lightother than reflected infrared light. φ can be calculated using thefollowing equation.

φ==tan⁻¹|(p1−p3)/(p2−p4)|

D described with reference to FIG. 6 can be calculated as follows.

D=T×φ/2π

A distance L to the subject will be calculated next using equation 1.Here, p1 to p4 can be acquired by performing exposure while a phase isseparated by 90° for one cycle of the emitted infrared light,accumulating generated electric charges and converting the electriccharges into an infrared light signal. In FIG. 17b , these are indicatedas first to fourth exposure periods.

As described above, in the distance measurement method illustrated inFIG. 17, because a distance is measured by using four Z pixels andcalculating differences, it is possible to remove influence of infraredlight other than reflected infrared light. Therefore, compared to thedistance measurement method described with reference to FIG. 6, it ispossible to perform measurement with high accuracy,

Imaging Method

FIG. 18 is a diagram illustrating an imaging method in a thirdembodiment of the present technology. A case will be assumed where thefirst to the fourth exposure periods described with reference to FIG. 17are respectively set for Za, Zb, Zc and Zd in FIG. 18. First, ON signalsare input to RSTs of the infrared light converting blocks 620, 630, 640and 650 to discharge the electric charges held in the infrared lightelectric charge holding units 621, 631, 641 and 651 (T1). Note that nameof the infrared light converting blocks will be omitted in the followingdescription.

At the same time as input of signals to the RSTs, ON signals are inputto the OFD4, the OFD3, the OFD2 and the OFD1, and the photoelectricconverting units 111, 121, 131 and 141 are reset. After reset isfinished, input of the ON signals to the RSTs and the OFD1 to the OFD4is stopped (T2).

Then, emission of infrared light is started, and ON signals are input tothe TR4, the OFD3, the OFD2 and the OFD1 (T3). By this means, exposurebased on the reflected infrared light is performed at the pixel 140, andelectric charges are accumulated in the infrared light electric chargeholding unit 621.

Then, input of the ON signals to the TR4 and the OFD3 is stopped, and ONsignals are input to the TR3, the OFD4, the OFD2 and the OFD1 (T4). Bythis means, exposure based on the reflected infrared light is performedat the pixel 130, and electric charges are accumulated in the infraredlight electric charge holding unit 631.

Then, input of the ON signals to the TR3 and the OFD2 is stopped, and ONsignals are input to the TR2, the OFD4, the OFD3 and the OFD1 (T5). Bythis means, exposure based on the reflected infrared light is performedat the pixel 120, and electric charges are accumulated in the infraredlight electric charge holding unit 641.

Then, input of the ON signals to the TR2 and the OFD1 is stopped, and ONsignals are input to the TR1, the OFD4, the OFD3 and the OFD2 (T6). Bythis means, exposure based on the reflected infrared light is performedat the pixel 110, and electric charges are accumulated in the infraredlight electric charge holding unit 651.

Then, input of the ON signals to the TR1 and the OFD4 is stopped (T7).Thereafter, operation from T3 to T6 is repeated the predetermined numberof times. By this means, electric charges based on the reflectedinfrared light are accumulated in the infrared light electric chargeholding units 621, 631, 641 and 651.

Then, ON signals are input to the SELs of the infrared light convertingblocks 620 and 630 (T8). By this means, an infrared light signal basedon the electric charges held in the infrared light electric chargeholding units 621 and 631 is generated. Then, input of the ON signals tothe SELs of the infrared light converting blocks 620 and 630 is stopped,and ON signals are input to the SELs of the infrared light convertingblocks 640 and 650 (T9). By this means, an infrared light signal basedon the electric charges held in the infrared light electric chargeholding units 641 and 651 is generated. As described with reference toFIG. 16, because the pixel group 660 of Z pixels are disposed across twolines, it is necessary to input a signal of the SEL for each one line toacquire an infrared light signal. Then, input of the ON signals to theSELs of the infrared light converting blocks 640 and 650 is stopped, anda distance measurement period is finished (T10).

By acquiring the above-described infrared light signal based on theelectric charges held in the infrared light electric charge holdingunits 621, 631, 641 and 651, it is possible to obtain an infrared lightsignal whose phase is shifted by 90°. The distance measurement unit 50measures a distance to the subject on the basis of these infrared lightsignals.

In this manner, according to the third embodiment of the presenttechnology, it is possible to use a distance measurement method of ascheme in which exposure of the reflected infrared light is performed inseparated four phases. By this means, it is possible to remove influenceof infrared light other than reflected infrared light, so that it ispossible to improve accuracy of distance measurement.

Fourth Embodiment

In the above-described third embodiment, Z pixels of the pixel group 660are disposed adjacent to each other. Meanwhile, in a fourth embodimentof the present technology, Z pixels are disposed at positions of Gpixels in the Bayer array in the infrared light converting block. Bythis means, it is possible to facilitate de-mosaic processing.

Operation of Solid-State Imaging Apparatus

FIG. 19 is a diagram illustrating an infrared light converting block inthe fourth embodiment of the present technology. The infrared lightconverting blocks 620, 630, 640 and 650 in FIG. 19 are configured withone Z pixel and three visible light converting pixels. However, theinfrared light converting blocks 620, 630, 640 and 650 in FIG. 19 aredifferent from the infrared light converting blocks 620, 630, 640 and650 described with reference to FIG. 16 in that Z pixels are disposed atpositions of G pixels in the Bayer array of the respective photoelectricconverting blocks. Because configurations of the solid-state imagingapparatus 20 and the imaging system 1 other than this are similar tothose of the solid-state imaging apparatus 20 and the imaging system 1in the third embodiment of the present technology, description will beomitted. Further, as the distance measurement method, it is possible toemploy a distance measurement method of a scheme in which exposure ofthe reflected infrared light is performed in separated four phases in asimilar manner to the third embodiment of the present technology.

As described above, the image processing unit 40 can perform de-mosaicprocessing on the visible light signal output from the solid-stateimaging apparatus 20. This de-mosaic processing is processing forinterpolating a signal of color insufficient in each pixel, and, in thecase where the processing is applied to the Z pixel, it is necessary tointerpolate signals corresponding to three of red light, green light andblue light. This interpolation can be performed by calculating anaverage value of the visible light signals output by the visible lightpixels disposed around the Z pixel among the visible light pixelscorresponding to the corresponding color.

However, for the visible light signal corresponding to green light inthe Z pixel, interpolation can be performed using a signal of a G pixelincluded in the same infrared light converting block. By this means, itis possible to simplify de-mosaic processing of the visible light signalcorresponding to green light.

In this manner, according to the fourth embodiment of the presenttechnology, by disposing Z pixels at positions of the G pixels in theBayer array, it is possible to perform interpolation using the visiblelight signals of G pixels included in the same infrared light convertingblock upon de-mosaicing. By this means, it is possible to simplifyde-mosaic processing of the visible light signals.

5. Fifth Embodiment

In the above-described fourth embodiment of the present technology,electric charges generated at the Z pixels are transferred and held by apair of the electric charge transferring unit and the electric chargeholding unit. Meanwhile, in the fifth embodiment of the presenttechnology, two pairs of the electric charge transferring units and theelectric charge holding units are used. By this means, it is possible toimprove accuracy of distance measurement.

Arrangement of Pixels

FIG. 20 is a diagram illustrating an arrangement example of pixels inthe fifth embodiment of the present technology. A pixel 140 which is a Zpixel (Za) in FIG. 20 is different from the Z pixel 140 described withreference to FIG. 4 in that an electric charge transferring unit 144 andan electric charge holding unit 155 are further provided. Note thatother Z pixels (Zb, Zc and Zd) in FIG. 20 are different from the Zpixels described with reference to FIG. 4 in a similar manner.

Circuit Configuration of Pixel

FIG. 21 is a diagram illustrating a configuration diagram of a pixel inthe fifth embodiment of the present technology. FIG. 21 illustratescircuit configurations of the Z pixel 140, the signal generating unit150 and the electric charge holding units 151 and 155 in the infraredlight converting block.

The pixel 140 in FIG. 21 does not have to include the over flow drain143. Instead, an electric charge transferring unit 144 is furtherprovided. Further, the signal line 101 includes a TR5 instead of theOFD4. The transfer 5 (TR5) is a signal line for transmitting a controlsignal to the electric charge transferring unit 144. As illustrated inFIG. 21, an anode of the photoelectric converting unit 141 is grounded,and a cathode is connected to sources of the electric chargetransferring units 142 and 144. Gates of the electric chargetransferring units 142 and 144 are respectively connected to the TR4 andthe TR5. A drain of the electric charge transferring unit 142 isconnected to one end of the electric charge holding unit 151 in asimilar manner to the pixel 140 described with reference to FIG. 3.Meanwhile, a drain of the electric charge transferring unit 144 isconnected to one end of the electric charge holding unit 155.

The signal generating unit 150 is different from the signal generatingunit 150 described with reference to FIG. 3 in that MOS transistors 156to 158 are further provided. As illustrated in FIG. 21, drains of theMOS transistors 156 and 157 are connected to a Vdd. A source of the MOStransistor 156 and a gate of the MOS transistor 157 are connected to oneend of the electric charge holding unit 155 to which the drain of theelectric charge transferring unit 144 described above is connected. Theother end of the electric charge holding unit 155 is grounded. A sourceof the MOS transistor 157 is connected to a drain of the MOS transistor158, and a source of the MOS transistor 158 is connected to the signalline 102. As illustrated in FIG. 21, the signal line 102 is configuredwith two signal lines, and transmits signals respectively output fromthe MOS transistors 154 and 158. Gates of the MOS transistor 156 and theMOS transistor 158 are respectively connected to the signal lines RSTand SEL.

The MOS transistor 157 is a MOS transistor which generates a signal inaccordance with the electric charge held in the electric charge holdingunit 155. The MOS transistor 158 is a MOS transistor which outputs asignal generated by the MOS transistor 157 to the signal line 102 as animage signal. The MOS transistor 156 is a MOS transistor whichdischarges the electric charge held in the electric charge holding unit155.

In this manner, at the pixel 140 in FIG. 21, the electric chargegenerated by the photoelectric converting unit 141 can be separated andtransferred to the electric charge holding units 151 and 155. Becausethe configuration of the pixel other than this is similar to theconfiguration of the pixel, or the like, described with reference toFIG. 3, description will be omitted. Further, as a distance measurementmethod in the fifth embodiment of the present technology, it is possibleto use the distance measurement method described with reference to FIG.6. The configurations of the solid-state imaging apparatus 20 and theimaging system 1 other than this is similar to those of the solid-stateimaging apparatus 20 and the imaging system 1 in the first embodiment ofthe present technology, description will be omitted.

Imaging Method

FIG. 22 is a diagram illustrating an imaging method in the fifthembodiment of the present technology. FIG. 22 illustrates relationship,or the like, between an input signal and an output signal at the pixel140 described with reference to FIG. 20.

First, ON signals are input to the RST, the TR4 and the TR5 (T1). Bythis means, the photoelectric converting unit 141 is reset, and theelectric charges held in the electric charge holding units 151 and 155are discharged. After reset is finished, the above-described input ofthe ON signals to the RST, the TR4 and the TR5 is stopped (T2).

Then, infrared light is emitted from the infrared light emitting unit60, and an ON signal is input to the TR4 (T3). By this means, anelectric charge based on the reflected infrared light generated by thephotoelectric converting unit 141 is held in the electric charge holdingunit 151.

Then, emission of the infrared light by the infrared light emitting unit60 is stopped, and input of the ON signal to the TR4 is stopped. At thesame time, an ON signal is input to the TR5 (T4). By this means, anelectric charge based on the reflected infrared light generated by thephotoelectric converting unit 141 is held in the electric charge holdingunit 155.

Thereafter, operation of T3 and T4 is repeated the predetermined numberof times. By this means, electric charges based on the reflectedinfrared light are accumulated in the electric charge holding units 151and 155.

Then, an ON signal is input to the SEL (T6). By this means, infraredlight signals based on the electric charges held in the electric chargeholding units 151 and 155 are respectively output. Then, input of the ONsignal to the SEL is stopped, and the distance measurement period isfinished (T7). A distance is calculated by the distance measurement unit50 on the basis of the output infrared light signals.

Note that, in the case where light receiving sensitivity of infraredlight is insufficient, it is also possible to generate infrared lightsignals at the Zb, the Zc and the Zd in a similar manner, and add theseto be used for calculation of the distance.

In this manner, electric charges based on photoelectric conversion insynchronization with emitted infrared light are accumulated in theelectric charge holding unit 151. Meanwhile, in the electric chargeholding unit 155, electric charges obtained as a result of photoelectricconversion being performed at a timing where a phase is shifted by 180°with respect to the emitted infrared light, are accumulated. That is, itis possible to execute the first and the second exposure periodsdescribed with reference to FIG. 6 with one pixel. Therefore, comparedto a case where the first and the second exposure periods are executedwith different pixels, it is possible to reduce influence of variation,or the like, of sensitivity in photoelectric conversion, so that it ispossible to improve accuracy of distance measurement. Further, becauseall the electric charges generated by the photoelectric converting unit141 are transferred to the electric charge holding units 151 and 155, anover flow drain does not have to be provided at the pixel 140.

In this manner, according to the fifth embodiment of the presenttechnology, it is possible to generate two infrared light signalsrequired for measuring a distance, with one pixel. By this means, it ispossible to reduce influence of variation, or the like, of sensitivityin photoelectric conversion, so that it is possible to improve accuracyof distance measurement.

Modified Example

In the above-described fifth embodiment of the present technology, adistance is measured in a configuration where an electric chargetransferring unit and an electric charge holding unit of the Z pixelsare added to the infrared light converting block where Z pixels aredisposed at positions of G pixels in the Bayer array. Meanwhile, it isalso possible to measure a distance in a configuration where an electriccharge transferring unit and an electric charge holding unit are addedto the Z pixels in the first embodiment of the present technology.Specifically, electric charge transferring units are added to thephotoelectric converting unit 121 of the pixel 120 and the photoelectricconverting unit 141 of the pixel 140 described with reference to FIG. 4.An electric charge holding unit to which the added electric chargeholding units are commonly connected is further provided. By this means,it is possible to reduce influence of variation, or the like, ofsensitivity in photoelectric conversion, so that, in the case where theinfrared light converting block is configured with two infrared lightconverting units and two visible light converting units, it is possibleto improve accuracy of distance measurement.

In addition, the above-described embodiments are examples for embodyingthe present technology, and matters in the embodiments each have acorresponding relationship with disclosure-specific matters in theclaims. Likewise, the matters in the embodiments and thedisclosure-specific matters in the claims denoted by the same names havea corresponding relationship with each other. However, the presenttechnology is not limited to the embodiments, and various modificationsof the embodiments may be embodied in the scope of the presenttechnology without departing from the spirit of the present technology.

Also, the processing sequences that are described in the embodimentsdescribed above may be handled as a method having a series of sequencesor may be handled as a program for causing a computer to execute theseries of sequences and recording medium storing the program. As therecording medium, a hard disk, a CD (Compact Disc), an MD (MiniDisc),and a DVD (Digital Versatile Disc), a memory card, and a Blu-ray disc(registered trademark) can be used.

Effects described in the present description are just examples, theeffects are not limited, and there may be other effects.

Additionally, the present technology may also be configured as below.

(1)

A solid-state imaging apparatus including:

a visible light converting block that includes a plurality of visiblelight converting units in which light receiving faces for receivingvisible light are disposed and configured to generate electric chargesin accordance with a light receiving amount of the received visiblelight, and a visible light electric charge holding unit configured toexclusively hold the electric charges respectively generated by theplurality of visible light converting units in periods different fromeach other; and

an infrared light converting block that includes a plurality of infraredlight converting units in which light receiving faces which havesubstantially the same size as size of the light receiving faces of thevisible light converting units and which receive infrared light aredisposed and configured to generate electric charges in accordance witha light receiving amount of the received infrared light, and an infraredlight electric charge holding unit configured to collectively andsimultaneously hold the electric charges respectively generated by theplurality of infrared light converting units.

(2)

The solid-state imaging apparatus according to (1),

in which the visible light converting block includes the four visiblelight converting units and the visible light electric charge holdingunit.

(3)

The solid-state imaging apparatus according to (2),

in which the infrared light converting block includes the four infraredlight converting units and the infrared light electric charge holdingunit.

(4)

The solid-state imaging apparatus according to (2),

in which the infrared light converting block includes:

-   -   the two infrared light converting units;    -   the two visible light converting units; and    -   the infrared light electric charge holding unit configured to        collectively and simultaneously hold the electric charges        respectively generated by the two infrared light converting        units in the case of holding the electric charges generated by        the two infrared light converting units, and exclusively hold        the electric charges respectively generated by the two visible        light converting units in periods different from each other in        the case of holding the electric charges generated by the two        visible light converting units.        (5)

The solid-state imaging apparatus according to any of (2) to (4),

in which the visible light converting block includes the visible lightelectric charge holding unit and the four visible light converting unitsin which a red light converting unit which is the visible lightconverting unit configured to generate the electric charge in accordancewith red light, a green light converting unit which is the visible lightconverting unit configured to generate the electric charge in accordancewith green light, and a blue light converting unit which is the visiblelight converting unit configured to generate the electric charge inaccordance with blue light are arranged in a Bayer array.

(6)

The solid-state imaging apparatus according to any of (2) to (4),

in which the visible light converting block includes a red lightconverting unit which is the visible light converting unit configured togenerate the electric charge in accordance with red light, a green lightconverting unit which is the visible light converting unit configured togenerate the electric charge in accordance with green light, a bluelight converting unit which is the visible light converting unitconfigured to generate the electric charge in accordance with bluelight, a white light converting unit which is the visible lightconverting unit configured to generate the electric charge in accordancewith white light, and the visible light electric charge holding unit.

(7)

The solid-state imaging apparatus according to any of (2) to (4),

in which the infrared light converting block further includes aninfrared light electric charge transferring unit configured to transferthe electric charges respectively generated by the plurality of infraredlight converting units to the infrared light electric charge holdingunit by conducting electricity between the plurality of infrared lightconverting units and the infrared light electric charge holding unit ata same time.

(8)

The solid-state imaging apparatus according to any of (1) to (7),further including

an infrared light signal generating unit configured to generate a signalin accordance with the electric charge held in the infrared lightelectric charge holding unit.

(9)

An imaging system including:

an infrared light emitting unit configured to emit infrared light to asubject;

a visible light converting block that includes a plurality of visiblelight converting units in which light receiving faces for receivingvisible light are disposed and configured to generate electric chargesin accordance with a light receiving amount of the received visiblelight, and a visible light electric charge holding unit configured toexclusively hold the electric charges respectively generated by theplurality of visible light converting units in periods different fromeach other;

an infrared light converting block that includes a plurality of infraredlight converting units in which light receiving faces which havesubstantially the same size as size of the light receiving faces of thevisible light converting units and which receive infrared light emittedand reflected by the subject are disposed and configured to generateelectric charges in accordance with a light receiving amount of thereceived infrared light, and an infrared light electric charge holdingunit configured to collectively and simultaneously hold the electriccharges respectively generated by the plurality of infrared lightconverting units;

an infrared light signal generating unit configured to generate a signalin accordance with the electric charge held in the infrared lightelectric charge holding unit; and

a distance measurement unit configured to measure a distance to thesubject by measuring a time period from the emission at the infraredlight emitting unit to the light reception at the infrared lightconverting unit of the infrared light converting block on the basis ofthe generated signal.

(10)

A distance measurement method including:

an infrared light emitting step of emitting infrared light to a subject;

an infrared light signal generating step of generating a signal inaccordance with electric charges held in an infrared light electriccharge holding unit in an infrared light converting block including aplurality of infrared light converting units in which light receivingfaces which have substantially the same size as size of light receivingfaces of visible light converting units in a visible light convertingblock and which receive infrared light emitted and reflected by thesubject are disposed and configured to generate electric charges inaccordance with a light receiving amount of the received infrared lightand the infrared light electric charge holding unit configured tocollectively and simultaneously hold the electric charges respectivelygenerated by the plurality of infrared light converting units, thevisible light converting block including a plurality of visible lightconverting units in which the light receiving faces for receivingvisible light are disposed and configured to generate electric chargesin accordance with a light receiving amount of the received visiblelight and a visible light electric charge holding unit configured toexclusively hold the electric charges respectively generated by theplurality of visible light converting units in periods different fromeach other; and

a distance measurement step of measuring a distance to the subject bymeasuring a time period from emission of the infrared light to the lightreception at the infrared light converting unit of the infrared lightblock on the basis of the generated signal.

REFERENCE SIGNS LIST

-   1 imaging system-   10 lens-   20 solid-state imaging apparatus-   30 signal processing unit-   40 image processing unit-   50 distance measurement unit-   60 infrared light emitting unit-   100 pixel array unit-   110, 120, 130, 140, 160, 170, 180, 190 pixel-   111, 121, 131, 141, 161, 171, 181, 191 photoelectric converting unit-   112, 123, 132, 143 over flow drain-   113, 123, 133, 142, 144 electric charge transferring unit-   119, 129, 139, 149 color filter-   150 signal generating unit-   151, 155, 159 electric charge holding unit-   152 to 154, 156 to 158 MOS transistor-   200 vertical driving unit-   300 horizontal transferring unit-   400 analog digital converter-   610 visible light converting block-   611 visible light electric charge holding unit-   620, 620, 640, 650 infrared light converting block-   621, 631, 641, 651 infrared light electric charge holding unit

1. A solid-state imaging apparatus comprising: a visible light converting block that includes a plurality of visible light converting units in which light receiving faces for receiving visible light are disposed and configured to generate electric charges in accordance with a light receiving amount of the received visible light, and a visible light electric charge holding unit configured to exclusively hold the electric charges respectively generated by the plurality of visible light converting units in periods different from each other; and an infrared light converting block that includes a plurality of infrared light converting units in which light receiving faces which have substantially the same size as size of the light receiving faces of the visible light converting units and which receive infrared light are disposed and configured to generate electric charges in accordance with a light receiving amount of the received infrared light, and an infrared light electric charge holding unit configured to collectively and simultaneously hold the electric charges respectively generated by the plurality of infrared light converting units.
 2. The solid-state imaging apparatus according to claim 1, wherein the visible light converting block includes the four visible light converting units and the visible light electric charge holding unit.
 3. The solid-state imaging apparatus according to claim 2, wherein the infrared light converting block includes the four infrared light converting units and the infrared light electric charge holding unit.
 4. The solid-state imaging apparatus according to claim 2, wherein the infrared light converting block includes: the two infrared light converting units; the two visible light converting units; and the infrared light electric charge holding unit configured to collectively and simultaneously hold the electric charges respectively generated by the two infrared light converting units in the case of holding the electric charges generated by the two infrared light converting units, and exclusively hold the electric charges respectively generated by the two visible light converting units in periods different from each other in the case of holding the electric charges generated by the two visible light converting units.)
 5. The solid-state imaging apparatus according to claim 2, wherein the visible light converting block includes the visible light electric charge holding unit and the four visible light converting units in which a red light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with red light, a green light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with green light, and a blue light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with blue light are arranged in a Bayer array.
 6. The solid-state imaging apparatus according to claim 2, wherein the visible light converting block includes a red light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with red light, a green light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with green light, a blue light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with blue light, a white light converting unit which is the visible light converting unit configured to generate the electric charge in accordance with white light, and the visible light electric charge holding unit.
 7. The solid-state imaging apparatus according to claim 1, wherein the infrared light converting block further includes an infrared light electric charge transferring unit configured to transfer the electric charges respectively generated by the plurality of infrared light converting units to the infrared light electric charge holding unit by conducting electricity between the plurality of infrared light converting units and the infrared light electric charge holding unit at a same time.
 8. The solid-state imaging apparatus according to claim 1, further comprising an infrared light signal generating unit configured to generate a signal in accordance with the electric charge held in the infrared light electric charge holding unit.
 9. An imaging system comprising: an infrared light emitting unit configured to emit infrared light to a subject; a visible light converting block that includes a plurality of visible light converting units in which light receiving faces for receiving visible light are disposed and configured to generate electric charges in accordance with a light receiving amount of the received visible light, and a visible light electric charge holding unit configured to exclusively hold the electric charges respectively generated by the plurality of visible light converting units in periods different from each other; an infrared light converting block that includes a plurality of infrared light converting units in which light receiving faces which have substantially the same size as size of the light receiving faces of the visible light converting units and which receive infrared light emitted and reflected by the subject are disposed and configured to generate electric charges in accordance with a light receiving amount of the received infrared light, and an infrared light electric charge holding unit configured to collectively and simultaneously hold the electric charges respectively generated by the plurality of infrared light converting units; an infrared light signal generating unit configured to generate a signal in accordance with the electric charge held in the infrared light electric charge holding unit; and a distance measurement unit configured to measure a distance to the subject by measuring a time period from the emission at the infrared light emitting unit to the light reception at the infrared light converting unit of the infrared light converting block on the basis of the generated signal.
 10. A distance measurement method comprising: an infrared light emitting step of emitting infrared light to a subject; an infrared light signal generating step of generating a signal in accordance with electric charges held in an infrared light electric charge holding unit in an infrared light converting block including a plurality of infrared light converting units in which light receiving faces which have substantially the same size as size of light receiving faces of visible light converting units in a visible light converting block and which receive infrared light emitted and reflected by the subject are disposed and configured to generate electric charges in accordance with a light receiving amount of the received infrared light and the infrared light electric charge holding unit configured to collectively and simultaneously hold the electric charges respectively generated by the plurality of infrared light converting units, the visible light converting block including a plurality of visible light converting units in which the light receiving faces for receiving visible light are disposed and configured to generate electric charges in accordance with a light receiving amount of the received visible light and a visible light electric charge holding unit configured to exclusively hold the electric charges respectively generated by the plurality of visible light converting units in periods different from each other; and a distance measurement step of measuring a distance to the subject by measuring a time period from emission of the infrared light to the light reception at the infrared light converting unit of the infrared light block on the basis of the generated signal. 